This invention relates to amorphous chalcogenide films for use as photolithographic resists and the like, and, more particularly, to novel compositions and procedures for fabricating such films on a substrate.
Amorphous chalcogenide thin films have recently found utility in a number of applications in the electronics industry. For example, the chalcogenide glasses, such as As.sub.2 S.sub.3, As.sub.2 Se.sub.3, Se--Ge, and other binary and ternary glassy compounds of sulphur, selenium and tellurium, are becoming increasingly important as radiation-sensitive resist materials in the photolithographic fabrication of integrated circuits. The amorphous chalcogenide thin films have also been investigated for use as optical information storage media, as xerographic films, as films for ovonic memories and switches, and as anti-reflection coatings and UV-absorbing coatings for lenses and other optical systems.
In all of the various aforementioned applications, fabrication of the amorphous chalcogenide thin films on a substrate has typically been effected by vacuum deposition techniques, i.e., either by thermal evaporation or by sputtering. In addition to the relatively high cost of these techniques, vacuum deposited films generally suffer from a lack of controllable reproducibility in their stoichiometry, morphology and microstructure. Moreover, solution coating techniques have heretofore been generally avoided due to the fact that the only previously known solvents for the chalcogenides, i.e., aqueous alkalies and acids, are reactive with the chalcogenides and convert them to crystallizable compounds.